The present invention generally relates to a method and a system for forming an energy field in a resonant chamber, and more particularly relates to a system and a method for separating contrary matter from a working material using ultrasonic energy.
The popularity of electrophotographic imaging compounds, such as dry toner used in laser and xerographic imaging devices, constitutes a growing concern in the area of waste paper recycling. Traditionally, documents have been imaged or printed using water or oil based inks, which are adequately removed using conventional deinking techniques. One such conventional deinking technique requires that the waste paper be mechanically pulped and placed in contact with an aqueous medium containing a surfactant. The oil and water based inks are separated from the pulp fibers as a result of the mechanical pulping and the action of the surfactant. The dispersed ink is then removed from the paper pulp by a washing process and/or a floatation process.
Conventional deinking processes have had little success when the waste paper is contaminated with an electrophotographic imaging compound. A factor contributing to the limited success of conventional deinking processes, is the fact that electrophotographic imaging compounds, such as dry toners, are attached to the imaging medium using heat or the combination of heat and pressure. The use of heat causes the electrophotographic imaging particles to fuse to the paper surface and to one another. Conventional deinking processes attempt to overcome this fusion problem by increasing the required time for pulping, by increasing the water temperature required in the pulper, and by raising the pH level of the liquid in the pulping apparatus.
The conventional deinking processes are costly in terms of energy, material, and various environmental factors, such as waste water treatment, personnel training, regulatory affairs, and the like. The burden of recycling waste paper contaminated with an electrophotographic imaging compound, such as dry toner, using conventional deinking processes, results in a low grade paper product that is costly to produce.
The present invention addresses the above-described limitations of the conventional processes for deinking waste paper contaminated with electrophotographic imaging compounds. The present invention provides an approach to reduce the dependency on processing chemicals, and to reduce the overall cost of processing waste paper contaminated with an electrophotographic imaging compound. An additional advantage of the present invention is that the recycled paper stock contains fewer particulates of an electrophotographic imaging compound, thus producing a higher quality recycled paper product.
In one embodiment of the present invention, a system is provided for separating contrary matter from a working material. The system includes a processing element having a circular cross section that is adapted to receive the working material contaminated with the contrary matter. The processing element is also adapted to provide an egress for the working material and the separated contrary matter. Further, a number of transducers, such as strips of piezoelectric film, are attached to the outer surface of the processing element to construct a resonant chamber. The transducer elements are also coupled to an exciter that provides a steady state square wave excitation that causes the transducer elements to vibrate. The vibration of the transducer elements produces an energy field within the resonant chamber that impacts the working material contaminated with the contrary matter. The impact of the energy field on the working material, within the processing element, causes the contrary matter to separate from the working material.
The above described apparatus benefits the waste paper recycling industry in that dry toner, such as thermoplastic toner, can be separated from paper fibers in a paper slurry in a more efficient manner, as compared to conventional deinking techniques. For example, reduced costs are recognized in the pulping operation, because the water temperature required in the pulper can be reduced, chemical additives in the pulping operation are eliminated, and the pulping operation itself can have a reduced cycle time. Moreover, the system of the present invention may also increase revenues for a waste paper recycler because, the present invention causes mircofibrillation of the paper fibers in the paper slurry, which allows the waste paper recycler to produce a higher quality recycled paper product without additional energy input in the refiner stage.
In accordance with another aspect of the present of invention, a method is preformed in a resonant chamber for separating contrary matter from a working material. The working material may be of a lignocellulosic material, a biochemical compound, or the like. The working material is introduced into the circular cross section processing element where the separation of the contrary matter from the working material occurs. While the working material is within the processing element, the transducers coupled to the outer diameter of the processing element are excited with an excitation source to produce an energy field centrally disposed within the processing element itself. Separation of the contrary matter from the working material occurs when the contaminated working material comes into contact with the centrally disposed energy field. The effectivity of the separation process is dependent upon the amount of applied energy the working material is subjected to within the processing element. After passing through the energy field, the working material will exit the processing element where the separated contrary matter and the working material are sorted.
The above described approach benefits other types of working material that can be suspended in a liquid medium, including a liquefied working material. In this manner, a working material contaminated with contrary matter can be suspended in a liquid medium and subjected to an ultrasonic energy field to separate contrary matter. The application of the ultrasonic energy field to the liquid medium causes the contrary matter and the working material to separate from one another and further causes fusion of the separated contrary matter, which facilitates removal of the separated contrary matter.
To accommodate a variety of working materials, the processing element diameter may be altered to suit the size and type of contaminated working material. Further, several processing elements of differing internal diameter may be serially connected so that the liquid medium holding the working material is subjected to various energy fields. In this manner, a working material contaminated with multiple types of contrary matter may be processed in a single closed loop system. Moreover, the method is environmentally friendly in that the addition of a chemical catalyst is not necessary.
In accordance with another aspect of the present invention, an electronic driver is provided that is suitable for use with the transducer assembly to generate the ultrasonic energy field within the processing element. The electronic driver circuit utilizes isolatable power sources to drive the output stage that generates a clock-like output signal. The clock-like output signal is fed into a serial resonant circuit that is made up of a torodial shaped inductor and the transducer elements. The isolatable power sources of the electronic driver circuit may be of the DC to DC regulator type or may be of the AC to DC converter type.